Many people enjoy viewing movies and other video images at their leisure, in the privacy of their homes, on television monitors or other types of display screens. The ready availability of recorded commercial movies as well as other video material on VHS tapes and more recently, on DVDs, has greatly increased the popularity of large screen televisions, and various types of monitors for viewing such video materials. In addition, a suitable video system can also be used for viewing digital photographs, over the air television programs, cable or satellite programming, and if coupled to an outside network through a suitable computing device, can even be used for browsing the Internet.
Others have taken the entertainment concept one step further by setting up a home theater system that employs a projector to project video images onto a screen mounted at the front of the room, or other appropriate surface. These projector systems provide excellent viewing quality while simulating a large screen, cinema-like experience. When setting a home theater projector system, however, a homeowner must face the relatively high cost of the projector and the problem of where to mount it. Many homeowners have chosen to mount the projector on the ceiling, which is expensive due to the time and labor necessary to mount it and hide the wiring used to provide power and a video signal to the projector. Furthermore, as a result of the complexity of this installation procedure, a homeowner most likely will be limited to viewing projected video images in a single room or area. It would therefore be desirable to enable the projection system to be more mobile and to reduce the overall cost of an entertainment system by combining the high cost projector with other components that enable multiple uses for the projector.
Prior art devices exist that incorporate a projector component in a display system that is usable with a computing device to view computer generated images, and also can readily be used for viewing movies on DVD or other video images. For example, a display platform was developed in the MIT Media Lab, as reported by Brygg Ullmer and Hiroshi Ishii in “The metaDESK: Models and Prototypes for Tangible User Interfaces,” Proceedings of UIST 10/1997:14–17. The metaDESK includes a near-horizontal graphical surface used to display two-dimensional geographical information. A computer vision system inside the desk unit (i.e., below the graphical surface) includes infrared (IR) lamps, an IR camera, a video camera, a video projector, and a pair of mirrors. The mirrors reflect the graphical image projected by the projector onto the underside of the graphical display surface, so that the image is viewable from above the display surface. Since a considerable portion of the cost of the metaDESK is for the projector, it would clearly be desirable to employ the projector to view images in larger perspective, by projecting the images onto a screen or adjacent wall. It would also be desirable to make the metaDESK more mobile, to enable it to be moved to a desired location where the images are projected onto a nearby wall or screen that is larger than the display surface of the metaDESK to be viewed in comfort.
Another prior art device was disclosed in several papers published by Jun Rekimoto of Sony Computer Science Laboratory, Inc. in collaboration with others. These papers briefly describe two display systems, which are referred to respectively as a “HoloWall” and a “HoloTable.” Both of these display systems use a projector to project images onto a rear of a display surface. The rear projection panel, which is vertical in the HoloWall and horizontal in the HoloTable, is semi-opaque and diffusive, so that rear projected images are clearly visible. Again, it would be desirable to use this projector in the HoloWall or HoloTable to project video images onto a larger wall or screen that is separate from either of these systems.
The relatively expensive projector in these prior art display systems should preferably be selectively usable to display images either on the display surface included with the display system or on another external surface to provide more cost effective use of the projector. In addition, it should be relatively easy to changes modes from viewing the image on the display surface of the system, to viewing the image on the external surface. By thus switching viewing modes, a user would be able to enjoy a home theater projector experience, but in a more cost effective manner, since the projector is being utilized for more than one purpose, but would also enjoy the benefits of the display system when the projector is used to project images on the display panel. Providing the consumer with another mode for utilizing the expensive projector is more appealing to a consumer and ensures greater marketing opportunities for such a display system, since there is no need for the consumer to purchase a second projector for use in a home theater.
The metaDESK and the HoloTable and HoloWall display systems include a video camera that is used to image the surface of the display table to detect objects. However, it would be desirable to use the video camera in a second mode to image a person or persons sitting within the viewing range of the video camera, when the projector is being used to project an image onto the external surface. This arrangement would be useful in video conferencing, to enable a user to view an image of another person involved in the video conference, while the other person sees an image of the user provided by the video camera.